Expansible core



Sept. 19, 1933.

G. F. MULLIN EXPANSIBLE CORE Filed March 19, 1931 INVENTOR George F. Mullin 3%, QW

ATTORNEY!) 5 the vulcanization oftire' casings, and to proce- Patented Se t. 19, 1933- n, (1,927,803T V George'F. Mullin, Akron, Ohimassignor to The].

FireStne, Tirefi&' Rubber Company, Akron,

7 Ohio,'acor'poration of 01110 ,c h pplicationMarch 19, 19311;s ri l n rszsgvz This invention relates to 'expansible cores and to methods ofmaking the sam e', and more especially it relates to hollow annular cores of elastic material, such as the rubber water-bagsused. in

,dure for manufacturing the samel .The chief objects .of the veftionra're to prevent leakage of fluid from the core; to improve thefunionof thje rubber coreistrueturewith the tubular stem or connection therein; andto-p'ro- 1" vide animproved method. of mounting the tubular stem" in t'he'fubber 'core structure. Other obceeds.

Of the accompanying drawing: j Figure 1 is a side elevation of an expansible core embodying and made according to. the invention,

in its preferred form;

Figure 2 is a section on the line 2- 2 of Figure 1 on a larger scale;

Figure 3 is a section on the line 3-3 of Figure 2; Figure 4 is a plan view of the structure shown in Figure 3; and

Figure 5 is an elevation of a tool used in the manufactured the improved expansible core.

Referring to the drawing, is a hollow, annular, expansible core of rubber such as commonly is used inside of a tire casing during the vulcanization thereof, for distending the tire casing into conformity with an encompassing mold, the inner peripheral portion 10 of the core, which lies bee tween the bead portions of the tire, being considerably thicker than the rest of the core. Extending radially through the thickened portion 10 of the core, and molded therein, is a tubular stem or connection, generally designated 1'1,

tively large pad 19 of relatively stiff fibrousrubber composition covering the latter. An elongate washer 20 is mounted upon the inner end portion of the stem structure and forced against the pad 19 by a cap 21 that is formed with a tubular out "or the 'expansiblefcore 10.

the. jects will be manifest as the specification 'pro-- I.

The flange 13 is overlaid with a layer of rubber composition 18, and a rela-' axial extension 21* that is e'xte'riorly threaded to fit the threads 14 the inner end of the] structure 1 2; Thecaplmis' formed with apertures 22," 22 oftany 'suitable size and shape, and witha square axial aperture 23 for receiving a suitable .toolby which the cap may be turnedto tighten it against thdwasher 20;. The apertures, 22, 23

fconstitute passages for ffluid vthat flows into and ..anfexternally'threaded tubularfstfem 24 is ber 12, said 'stem extendingthrou'ghtheiintervening rubber between the end of thef'me'mber 12 dout' r e'na portioiijofthe I .Tl 1'e oute'r end 'ofthe Emember12f is, disposed Withintheportion 1020f th coreljsli'ghtly below surface at "theinne'r' pen'pneryor the latter,

and the inner periphery" of the core. vA washer 25 is mounted upon the stem 24' and pressed against the core-wall by a nut 26 threaded'onto said stem. .The stem 24 is formed with diametrically opposed flat faces 27, 2'7 for receiving a Wrench or other suitabletool (not shown) for, turning the stem to thread it into or out of the member12. V I

In Figure 5 is shown a suitable tool for turning the cap 21, said tool; comprising an elongate cylindrical body portion 28 adapted to extend" through the tubular stem 24, a squareend portion 29 adapted to fit within the square'aperture 23 of the cap 22, and a pin'30 extending transversely through the opposite end portion of the tool for grasping the same. p In the manufacture of the improved expansible .cores, the respective .parts of the core 10 and connection 11 are assembled as shown, the rubber parts of course being inunvulcanized condition, and the cap 21 and' nut 26 are. setup- I moderately tight, but not tight'fenough to distort or displace the rubber. In this condition thecore h 9.5

is mounted in a mold and vulcanized by heatand internal pressure. in theusual manner. During the vulcanizing operation the rubbershould-vulcanize to the connection 11, but usually this is imperfectly effected so thatthere are local regions of slight separation which heretofore have per-- mitted leakage of fluid from the core during use.

- After the core is vulcanized,thecap 21 is set up tightly by the use of the tool 28, and the nut 26 also is .set up tightly, with theresult that the vulcanized rubber surroundingflthe connection ,1 5 i 11 is put under pressure, and displacement of 1 the rubber due to said pressure causes it firmly to press against the exterior ofthe connection so that leakage about the connection is avoided- The presence of the plies 17 and'19 of fibrousllfl than ordinary rubber when heated.

' The invention provides an improved expansible .core which will not leak around thestem or connection,- and the inwardly projecting stem 24 thereof maybe easily and quickly replaced when it becomes worn or bent;

Modification may be resorted to within the'- ing a washer-adjacent the inner end of the body scope of the appended claims which are notlimited Wholly to the specific construction shown or exact procedure described. c

What is claimed is:

Y molded rubber structure, avtubular; stem extend- 7 ing partially through the wall thereof and an apertured cap threaded into the end of theste'mwithin the core, said cap being formed with an internal'wrench socket whereby said capmay be 7 'further threaded into the'end of the stern after v of thestem.

thefcore hasbeen molded for -compressing ma end portion or said stem, and a tubular bolt threaded into the same endof theflstem for urg ing the-washer against the core-rwall; the bore jof, said tubular; boltbeing iorme'dwithawrerich socket whereby the boltmayf be threaded by alt col introduced through the tubularstem, V J

larbolt.

3. An expansible core comprising a hollow rubber structure, and a tubularconnection therefor comprising a tubular body structure molded into the core wall with its outer end short of the outer face thereof, a tubular stemthreaded into the outer end of 'said bodystructure, a washer on said stem, and a nut threadedontosaid stem forurging the-washer against the core-wall and into seating relation with the outer end of the tubular body structure.

4. A combination as defined in claim 3 includstructure of the connection, and a member threaded to said body structure urging the washer I against"the inner surface of the core-wall. 1. An expansible core comprising a hollow 5. A combination-as defined in claim 3t including a flange on the inner end of the body structure of the connection, and a tubular flanged bolt threaded into said body structure, the bore of said bolt being formed with a ,Wrench socket for the'ap'plication of awrench to turn said bolt 'for urging the flanged bolt against the inner surface of the coreall and for compressing the material of the core between thefianged bolt and the flange on the body structure.

6; A combination as defined in claim 2 in which 'a fibrous composition washer'is interposed between the surface ofthe core and 'the washer against the core wall byjthe tubu-x which is urged 

